I got a Romi chassis from Pololu.
I put a link up at youTube if anyone is interested in seeing what this looks like, and what the power/motor board they sell with it looks like. There's only a couple hits on youTube for that chassis, so I thought I'd share what I learned.
I'm not affiliated with Pololu. I also use a <competing company> board. Sorry about that, arduino (but I have made it up to arduino with a couple donations (https://www.arduino.cc/en/main/donate)).
Feel free to ask me any questions but it's all pretty straightforward. In the video, I'm not doing anything with it, but I think I'm going to have something this weekend, and something else coming up when I get a few components in the mail.
I'm writing my own library for it (it will be more fleshed out when I get encoders hooked up). Pololu has one at gitHub, but I'm sort of confused by why they did things the way they did (all static members in the class, no constructor that lets you set output pins from your board. It's weird.)